There was barely an empty seat in the Old Whaling Church Monday night. As the hour neared eight o’clock, a crowd of spectators began a game of musical chairs as they attempted to find an unfilled space close to friends or family. But in the end, finding a seat didn’t much matter — not with so much time spent in standing ovations for the musical performances.

It was opening night of the 39th season of the Martha’s Vineyard Chamber Music Society’s summer concert festival. Society founder and artistic director Delores Stevens took her usual position at the piano, joined by concert headliner William DeRosa on cello, Yoon Kwon on violin and Carrie Dennis on viola.

The group performed five pieces for a captivated audience. The performers’ chemistry and energy emerged in the first performance of Mozart’s piano quartet in G minor, and grew steadily through each piece. Ms. Stevens and Ms. Dennis brought loud applause from the audience with an energetic performance of Hindemith’s sonata for viola and piano.

Mr. DeRosa and Ms. Stevens struck a more somber and emotional note with a piece by Rachmaninoff. The performers shared the stage with a colorful poster painted by the late Gretchen Feldman, a small memento to remember the artist.

The event was held as a memorial concert for Mrs. Feldman, a former member of the chamber society board of directors. Mrs. Feldman passed away in November. Her husband, Sam Feldman, and their family sponsored the Monday and Tuesday night concerts as a tribute to his late wife. The concert was offered free of charge.

Mr. Feldman was seated in the front row of the church, flanked by friends and family who were clearly absorbed by the chamber music so loved by his wife. At intermission, Mr. Feldman rose to address the crowd.

Gretchen would be so pleased, he said, by the number of people who came to enjoy the concert and support the chamber music society. Explaining Mr. DeRosa’s return visit to the Island for the concert, Mr. Feldman shared the touching story of his wife’s introduction to the cellist at a small, private concert held inside Joan Smith’s barn in West Tisbury last year. She was enchanted by both the music and the setting. Mr. DeRosa played Brahms sonatas from memory, silhouetted by light through a window overlooking the Vineyard Sound.

“It was just a beautiful scene,” recalled Mr. Feldman in a recent Gazette interview. “Gretchen thought that this was a magical moment for her.”

Mr. Feldman later requested that Mr. DeRosa hold another private concert in the couple’s New York city apartment, and he agreed. Unfortunately, Mrs. Feldman’s illness progressed quickly, and she passed away before Mr. DeRosa was able to make that visit.

Once again, Mr. Feldman phoned Mr. DeRosa, this time to request that the cellist accompany him on his flight to Martha’s Vineyard to play at the burial of his wife. He declined, unwilling to carry his rare antique cello on a small plane. Instead, Mr. DeRosa drove to the Vineyard. He played for Mrs. Feldman’s burial the next day, and subsequently played at a service at the couple’s Vineyard home.

Mr. Feldman wept softly as his story unfolded, and many in the crowd did as well, joined in sadness at the loss of the late Mrs. Feldman.

“In my mind, William (DeRosa) exhibits the caring, love and compassion that all of us aspire to,” Mr. Feldman said in conclusion. His exit from the stage was followed by the performance by Ms. Stevens and Mr. DeRosa of Rachmaninoff’s sonata for cello and piano.

The musicians dedicated the piece to the memory of Gretchen Feldman.